ET-700

Nov. 5, 2026: Eton Pharmaceuticals (NASDAQ: ETON) reported preliminary results from a randomized, double-blind, placebo-controlled pilot study of ET-700, an investigational extended-release zinc acetate formulation for Wilson disease, in healthy volunteers.

In the 29-participant per-protocol primary analysis, hepatic copper uptake decreased 12% with ET-700 versus 46% with GALZIN and increased 11% with placebo, based on copper-64 PET/CT imaging. In the supportive intention-to-treat analysis (35 participants), uptake decreased 18% with ET-700 and 58% with GALZIN versus an 11% increase with placebo; GALZIN showed a greater effect than ET-700 (p=0.023).

Safety over four weeks favored ET-700: 1 of 12 participants had a treatment-related adverse event versus 8 of 12 on GALZIN and 3 of 12 on placebo; treatment-related GI adverse event rates were 0.30, 5.35, and 0.89 per 100 participant-days, respectively. No serious adverse events were reported.

The study enrolled 36 participants; active arms were GALZIN 50 mg three times daily or ET-700 75 mg twice daily plus matching placebo, each delivering 150 mg elemental zinc daily. Eton said the findings are preliminary and do not establish clinical efficacy in Wilson disease patients. The company plans additional study arms in 2027 to test faster-release formulations aimed at improving copper absorption inhibition while preserving tolerability.